


For The Sake Of Might

by Bloody_Twat



Category: Dr. STONE (Anime), Dr. STONE (Manga)
Genre: Anal Fingering, Anal Sex, Falling In Love, Lube, M/M, Requited Love, Senkuu abandons science, Senkuu joins Tsukasa, Senkuu joins the Empire of Might, Short & Sweet, Sweet, TKSTsukataSenkuuMonthJan2020, TKSevents, TheKingdomofShipping, Tsukasen, bottom!Senkuu, stone world, top!Tsukasa, 司千
Language: English
Status: Completed
Published: 2020-01-24
Updated: 2020-01-24
Packaged: 2021-02-27 05:55:06
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 2,356
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/22382188
Author URL: https://archiveofourown.org/users/Bloody_Twat/pseuds/Bloody_Twat
Summary: Senku had fallen for this man more than he had believed.
Relationships: Ishigami Senkuu/Shishiou Tsukasa
Kudos: 124
Collections: TsukasaSenkuuMonth - January 2020





	For The Sake Of Might

**Author's Note:**

> Hope this is alright.
> 
> Feel free to join the Dr. Stone shipping server! All ships are welcome!  
> We have lots of events scheduled, RP our fave ships, share headcanons, etc!
> 
> [Click here to join us!](https://discord.gg/HVejEr4)

“Join me,” Tsukasa isn’t joking around and Senku knows it. Knows very well that this is his last chance to side with Tsukasa or to stay in the kingdom of science.

Senku’s dedicated to science but it seems that for Tsukasa, he might just be able to push it back.

“Senku,” Taiju’s loud voice booms but Senku pays him no heed.

Only looks at Tsukasa as the other one offers him a small smile and extends his hand for Senku to take. He thinks that it’s to everyone’s surprise, mainly his own when he takes Tsukasa’s hand.

He sees that look of concern and then it’s gone, replaced by a wider smile. 

Tsukasa pulls him into his embrace and whispers to only him.

“I knew you’d make the right choice.”

Senku doesn’t move, doesn’t acknowledge him right up until Tsukasa lifts him up and runs. In the next second, he’s got Yuzuriha in his other arm and Taiju gives up.

Doesn’t even try to fight, just gives up an uncharacteristic move from him but he can’t help it. 

Senku’s never seen him give up just like this, had expected him to try to get Yuzuriha back and run off with her.

He’s startled by the thought that maybe Taiju isn’t doing that because Tsukasa’s got a hold on Senku too.

However, it’s already too late and Senku’s made up his mind. He offers Taiju a sad smile but he doesn’t see it. Taiju’s head is hung low as he follows Tsukasa.

Senku’s present for Asagiri Gen’s revival but there’s no real explanation to why he’s revived. Tsukasa doesn’t bother enlightening him either. At least not until Hyoga’s also revived.

“To keep an eye,” Tsukasa explains not that he needs to because Senku already knows.

At first, nothing really happens. Senku’s allowed to go wherever he wants and Tsukasa barely has any time to spend with him. He notices that he hasn’t seen Taiju or Yuzuriha for a few days but figures that they wouldn’t want to meet him anyway. 

Especially not after he’d given up on science. There’s regret welling up in his heart, regret at abandoning his dream, regrets for letting Yuzuriha and Taiju down but all in all, he forgets everything when one day, Tsukasa hugs him close.

“I’m sorry,” Tsukasa whispers.

It must be uncomfortable, having to get down to hug Senku but Tsukasa doesn’t complain. 

“For what?” Senku grins as he asks his question.

“For not being there past few days. I’ve been trying to organise everything,” Tsukasa mumbles into his hair.

“You do realise that I can help you, right?” Senku asks.

“Isn’t it because he doesn’t trust you?” Gen is suddenly standing close to them.

“Asagiri Gen,” Tsukasa’s gaze is imperious as he looks down at Gen who visibly trembles and starts sweating.

“Tsukasa-chan, I’m just here to tell you that Hyoga-chan’s come back. Please enjoy your time,” Gen leaves as quickly as he could but he doesn’t get very far.

“You wouldn’t come see me unless you had something more important,” Tsukasa frowns.

“It really doesn’t matter at the moment,” Gen offers a smile. It’s wicked and his pupils are blown wide like he’s enjoying this.

Tsukasa lets go of Gen and the mentalist takes the opportunity to run. Senku doesn’t miss the smirk on his face but refrains from commenting on it.

“You’re right, won’t you join me in ruling this empire of might?” Tsukasa asked, spreading his arms to show off his territory. 

Senku takes the chance to hug him. Asagiri Gen, he’d have to keep an eye on him, what benefit would there be for Senku to lead with Tsukasa? He figured it out but didn’t think it was a very important point.

“Say, Senku, can we…” Tsukasa trailed off, a light blush dusting his face as he spoke.

“Can we?” Senku grinned, already knowing. 

“I can tell you already know,” that cute expression of Tsukasa’s disappeared, replaced with the face he usually showed to those he led.

“Of course but be gentle,” Senku answered.

The look on Tsukasa’s face was gentle as he looked at Senku.

“Can I kiss you?” Tsukasa asked.

“We’ve kissed so many times yet you still insist on asking. Go ahead,” Senku tilted his head up.

Slow, gentle, all words that Senku, at first, would not have associated with him but it was different now. Tsukasa was his just as much he was Tsukasa’s.

He was enraptured by Tsukasa, to say the least. It was weird how quickly one could fall in love, or you could also say that it was odd how quickly these chemical reactions could be formed.

To be fair, maybe Senku should’ve prepared himself more mentally for what he had said okay to. He was currently waiting for Tsukasa’s return. He’d grabbed what he needed, more like Gen had appeared out of nowhere and had intruded into his private quarters and left a wooden bowl. Senku had taken a glance at it and wrinkled his nose.

It wasn’t the worst kind of lube, but it wasn’t the best either and, in this day, and age there were no condoms just randomly lying around for them to use.

“Senku,” Tsukasa seemed to marvel at the fact that Senku was waiting for him in his room.

“You’re here,” Tsukasa gulped, eyes opened wide as he slipped into their shared chamber.

“Did you think that I’d back out?” Senku smiled nervously.

Tsukasa didn’t answer, most likely too embarrassed to admit that he had doubted Senku.

“Can I?” Tsukasa gestured vaguely which made the ex-scientist laugh. He made his way to Tsukasa and tilted his head up, ready for a kiss that Tsukasa happily gave him.

This time, it wasn’t nearly as sweet as slow, there was almost desperation in the way Tsukasa kissed him. His hands went to his torso and they split so that Senku could take off his shirt under the hungry look in Tsukasa’s eyes. The second he’s gotten rid of his clothing, and so has Tsukasa, he’s being pulled into a kiss again.

“Eager,” Senku smirks.

“Only for you,” Tsukasa answers. 

Senku yelped when the taller one pulled him up but somehow, they managed to not break the kiss. However, it did end when Tsukasa put him down onto the extra cloth that dubbed as his bed.

Tsukasa took his sweet time kissing Senku’s exposed torso. He grinned when he got to Senku’s cock but avoided it, instead opting to bite gently at Senku’s thigh. Senku inhaled sharply at that, stopping himself from letting out a moan.  
It wasn’t the most comfortable thing to lie on nor was it how Senku thought his first time would go but what did it matter now?

“Lube,” Tsukasa stated to himself, dipping his fingers into the mixture inside the bowl and coating his fingers properly.

Senku sucked in a breath. Tsukasa’s fingers were pretty big compared to Senku’s. For a few seconds, he considering backing out and explaining his sudden fear but at the same time, he wanted it.

Wanted to see what was so amazing about this experience. For someone that had had close to no interest in this aspect previously, it suddenly felt too important. To test how long he could go, not that Senku had a lot of stamina but-  
“What are you thinking about? Do you want me to stop?” Tsukasa really did contrast the image he usually projected when he was with Senku.

“I’m fine, just give me a second, alright?” Senku breathed in and out, closing his eyes. When he did finally manage to calm his quickly beating heart, he nodded at Tsukasa to go for it.  
He tensed when he felt a finger prod at his hole but relaxed as best as he could, wincing at the foreign feeling of having a finger penetrate him.

“If it’s too much I can stop,” Tsukasa offered, worried for Senku.

“It’s fine, I’ll ten billion per cent tell you if anything’s wrong,” Senku nodded, somehow managing to distract himself as Tsukasa’s fingers went knuckle-deep into him.

He groaned as Tsukasa stopped and after a few seconds started to slowly pull out his finger and thrust it back in. Senku made a low noise in the back of his throat and grumbled something, to low for Tsukasa to notice.

A second finger started teasing at his rim, making Senku groan and buck his hips on accident. Tsukasa offered him a small smile before slipping his second lubed up finger into Senku.

An embarrassingly loud moan echoed around, much to Tsukasa’s delight who seemed to grow more confident as the seconds passed. He started moving his fingers and after a few thrusts, fit in a third one.

It was nice to see the scientist lose his usual composure, instead, replaced with one of wonder and content.

Seeing that Senku was back off to whatever land there was in his mind. Tsukasa took the opportunity, on his next thrust, to curls up his fingers. He did it a few times, changing the angle until suddenly Senku almost kicked him and yelped.

“What did you just do?” Senku inquired, bewildered at the sudden feeling.

“Secret,” Tsukasa answered, starting to hit Senku’s prostate head-on with every thrust of his fingers.

“Wait! I’m going to!” Senku shivered but just as he said it, the fingers inside of him slipped out.

Now, Senku had only seen Tsukasa naked once and he was thinking the same thing as back then. “He’s ten billion per cent too big.” Albeit the meanings were different now. 

“Senku,” Tsukasa moaned as he lubed up his dick.

Senku remained silent, watching the motion, the obscene squelch made him turn red he had probably been this colour for a while now.

“You look great, all flushed like this, beath me. It makes me very happy that you chose me,” Tsukasa leaned over so that he could properly kiss Senku.

“Are you ready or should I prep you more?” Tsukasa asked.

“It’s fine, just, stop if I tell you to,” Senku’s breath caught as Tsukasa teased the head of his dick at Senku’s entrance. 

“Of course,” Tsukasa nodded before frowning. “Relax, you’re going to hurt yourself.”

Senku tried to, taking deep breaths and hoping that his heart would stop hammering in his chest. He managed to force himself to relax his body. Once he relaxed, he felt Tsukasa’s hand slip into his, intertwining their fingers affectionately. 

“Ready?” Tsukasa asked, kissing him one more time.

“Yeah,” Senku sucked in a breath as Tsukasa started pushing in.

The stretch inevitably made Senku cringe. He couldn’t hold back the wince on his face but he didn’t ask Tsukasa to stop. It wasn’t unbearable as Tsukasa was going slowly just like Senku had asked of him.

“You’re so tight,” Tsukasa groaned into his ear.

“Don’t-” Senku moaned as Tsukasa’s hips jerked.

“Tell me when you’re ready,” Tsukasa started kissing Senku’s body, sucking a love bite into Senku’s collarbone.

The kisses didn’t stop until Senku felt like he had finally adjusted to Tsukasa’s girth. 

“Move,” Senku ordered and immediately gasped for breath, he wasn’t expecting how quick Tsukasa’s first thrust was, rendering him unable to speak. He could only mewl as Tsukasa started moving and thrusting faster when Senku started meeting his thrusts.

Senku’s arms wrapped around the back of his nape and pulled him down for another kiss, a slightly awkward angle that he didn’t seem to mind. A hand wrapped around Senku’s cock, jerking him off in earnest in time with Tsukasa’s thrusts. His other hand found it’s way to Senku’s hip, gripping it tightly as he thrust into him. 

He changed his angle a few time, nailing Senku's head-on and making him moan loudly. There was a satisfied grin on Tsukasa's face as he angled himself to keep nailing Senku's sweet spots and to hear him moan as he had previously again. 

“I love you, Senku,” perhaps Tsukasa was caught in the heat of the moment because he didn’t even seem to register what he had just said but that didn’t stop Senku from answering.

“I love you too, Tsukasa,” sweet words that were punctuated by loud moans.

It seemed that his words acted as fuel for Tsukasa so Senku tested this possibility, elated to learn that he really did speed up every time Senku told him that he loved him or just pulled him down for a kiss. It didn’t take much longer for Senku to come, encouraged by Tsukasa’s grunts and the unrelenting hand fisting his cock.

He came with a cry of Tsukasa’s name, arms letting go of Tsukasa’s neck as he did. Tsukasa came too, a thrust or maybe six more after Senku had. 

Senku remembered reading somewhere that having come up his butt would lead to a stomach ache but at the moment, he really couldn’t care.

Tsukasa collapsed next to him, making sure to not flatten Senku as he did.

He took the chance to brush one of Tsukasa’s long strands of hair from his face and frowned when Tsukasa got up.

“Did you mean it?” A soft whisper that he hadn’t expected to ever hear from Tsukasa.

“Mean that I love you? I ten billion per cent did, what about you?” Senku tried to get up but his limbs were shaking, unable to support his weight.

“I love you too, go to sleep. I’ll get Gen to bring us some water. I’ll wake you up when he brings it over,” Tsukasa smiled. A soft smile that would probably only be reserved for him.

They shared a long kiss and when it ended, Senku closed his eyes, letting sleep consume him.

________________________________________ 

“If we’ve made you carry too much you should just tell us, Senku! I can help,” Taiju smiled. Senku didn’t miss the way his eyes seemed to darken as he said those words.

“Work too much?” Tsukasa frowned.

“Yes, he’s limping,” Taiju answered.

“Oh,” Tsukasa smirked as he turned to Senku and winked.

“So, even Tsukasa can make a make a face like that,” Hyoga noticed and a small smirk grew underneath his mask.

**Author's Note:**

> This is [my Twitter](https://mobile.twitter.com/bloodytwat2) account if anyone’s interested. In case the link doesn’t work, my name is bloodytwat2.


End file.
